Efinix Titanium - Understanding PLL Phase Shifting; Manually Configuring the PLL

Titanium Interfaces User Guide
The Titanium PLL supports dynamic phase shifting. To enable it, click the Dynamic button
for the clock output. The calculator adds three additional pins that you use to control the
dynamic shifting. You need to specify the pin names.
As you make selections, the calculator determines the values for the pre-divider, multiplier,
post divider, and clock dividers that meet your settings. The GUI prompts you if you make
selections that are impossible to solve.
In manual mode, the interface displays the PLL's internal block diagram, and provides boxes
for you to set the values for the pre-divider, multiplier, post divider, and clock dividers. As
you adjust the values, the calculator prompts you if you make settings that result in F
VCO
values that are out of range or are impossible to solve. When you turn manual mode off,
the calculator adjusts the output clock frequencies to match the manual settings. If you have
incorrect settings for the pre-divider, multiplier, post divider, and clock dividers, when you
turn manual mode off, the calculator adjusts the values to ones that allow a valid solution.
When you are finished using the calculator, click Finish to save your settings and close the
GUI.
Understanding PLL Phase Shifting
The PLL supports clock phases from 0 to 315 degrees.
• You can set a phase shift for a clock output in the PLL Clock Calculator. The calculator
tries to get as close to that number as it can.
• If you want to set the phase shift manually, where you use the options to set the M, N,
O, divider, and shift values, the phase shift results you get are 0, 45, 90, 135, 180, 225, 270,
and 315.
You can also control the phase shifting dynamically. To turn on dynamic phase shifting, click
the Dynamic button next to the clock frequency in the PLL Clock Calculator. The GUI
adds three pins to control the shift. the shift select, and the shift enable. You can dynamically
change the phases simultaneously.
Figure 50: Example PLL Clock Phases
0°
45°
90°
135°
180°
225°
270°
315°
Manually Configuring the PLL
If you want more control over the PLL, you can manually configure it in the PLL Clock
Calculator using manual mode. To enable this mode, click the Manual Mode slider to turn it
on.
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